Electronic circuits and MEMS structures MEMS and similar microdevices are often formed by bonding and sealing a first substrate, on which various electronic circuits and micro electro mechanical system (MEMS) structures are formed, with a second substrate such as a glass substrate. Specifically, by performing microfabrication such as a thin film formation process and an etching process, various electronic circuits and MEMS are formed on each of a semiconductor substrate and a glass substrate. Negative and positive voltages are then applied to the glass and semiconductor substrate, respectively, while the substrates attached to each other are heated, and finally they are bonded by covalent bonding. Such bonding is called anodic bonding, and is widely used for MEMS manufacturing and packaging.
In Non-patent Literature 1, by anodically bonding a first substrate, on which a thermally-actuated high-frequency MEMS switching device is formed, and a second substrate, namely a glass substrate having through wiring, the high-frequency MEMS switching device is vacuum-sealed. Metallic thin films both on the high-frequency MEMS switching device and on the partially-etched second substrate are made contact together, and electrical connection between the substrates is established.
Meanwhile, Patent Literature 1 discloses a connection method, where thermo-compression bonding rather than anodic bonding is performed for semiconductor chips, and through-substrate interconnection is established by soldering.